The present invention relates to certain aspects of semiconductor devices and processing for forming them. In particular, the present invention relates to a single sided buried strap and a method for forming a single sided buried strap.
The present invention provides a method for clearing an isolation collar from a first interior surface of a deep trench at a location above a storage capacitor while leaving the isolation collar at other surfaces of the deep trench. A barrier material is deposited above a node conductor of the storage capacitor. A layer of silicon is deposited over the barrier material. Dopant ions are implanted at an angle into the layer of deposited silicon within the deep trench, thereby leaving the deposited silicon unimplanted along one side of the deep trench. The unimplanted silicon is etched. The isolation collar is removed in locations previously covered by the unimplanted silicon, leaving the isolation collar in locations covered by the implanted silicon.
The present invention also includes a method for clearing an isolation collar from a first interior surface of a deep trench at a location above a storage capacitor while leaving the isolation collar at other surfaces of the deep trench. A deep trench fill is recessed to a level of a bottom of a strap. A photoresist mask is deposited over portions of a liner in the deep trench. The photoresist mask is utilized to etch down unmasked portions of the liner to a top of polysilicon filling the deep trench. The photoresist mask is stripped. The isolation collar is etched, leaving the isolation collar in locations covered by the liner.
Still other objects and advantages of the present invention will become readily apparent by those skilled in the art from the following detailed description, wherein it is shown and described only the preferred embodiments of the invention, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.